Afterburner construction

ABSTRACT

An afterburner construction including the outer housing and chamber construction, and the construction of the burner itself which together provide a highly efficient afterburner for use with incinerators and furnaces.

United States Patent [191 Ehrlichmann 1 3,808,987 May 7, 1974 XXBN%N 86 32 1l mu 1 u 4 3 4 Patrick et a1.

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Primary Examiner-Kenneth W. Sprague Attorney, Agent, or Firm-Bugger, Johnson &

Westman [57] ABSTRACT An afterbumer construction includin ing and chamber construction the b [52] US. Cl. 110/8 A, 431/329 [51] Int Cl F23g 5/12 110/8 R, 8 A, 8 C, 18 C;

Field of g the outer housand the construction of urner itself which together provide a highly efficient afterbumer for use with incinerators and furnaces.

References Cited UNITED STATES PATENTS 12/1960 8 Claims, 8 Drawing Figures 2,965,051 110/8 3,730,112 Hutchinson et 110/8 Pmminm 7 m4 $808,987

SHEET 1. BF 2 INCINERATOR PATENTEMM H914 3308.987

SHEET 2 [IF-2 BLOWER BUR NE a CONTROLS 1 AF TERBURNER CONSTRUCTION BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to afterburner construction for use with incinerators and furnaces.

2. Prior Art In the present day environmental problems, the efficient burning of waste materials or combustible is sought after. The smoke and hydrocarbon pollutants from an ordinary furnace are objectionable, and will not in most instances pass existing pollution control standards. The present afterburner construction is designed to be added to existing incinerators and furnaces, in order to completely burn the objectionable pollutants so that the discharges are within pollution control standards.

SUMMARY OF THE INVENTION The present invention relates to an afterburner for an incinerator or furnace which includes means for providing a flame that is spread across a wide area to give uniform high heat where the smoke pipe from the incinerator enters the afterburner. The smoke pipe entrance also, is formed to cause the smoke entering the afterburner combustion area to change direction and thus swirl and mix with the flame from the burner for very efficient and complete burning.

The burnable particles in the smoke then are carried through the afterburner and the air is discharged with very little polluting effect.

A blower is used with the burner and provides a pressure at the combustion end of the afterburner. Thus pressure causes a flow from the combustion end through the outlet.

The afterburner is easy to construct and insures complete burning of solid particles in the smoke from incinerators and furnaces.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a vertical sectional view of an afterburner construction made according to the present invention;

pipe inlet FIG. 8 is a fragmentary sectional view taken as on line 8-8 in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT An afterburner construction illustrated generally at 10 includes the supporting legs 11 for supporting the main portion of the afterburner on a supporting surface 12. This supporting surface 12 may be a roof of a building, or it may be some special pad built adjacent to an existing incinerator or burner used for burning debris, paper, garbage, or the like. The afterburner construction can be used on any furnace or incinerator, but usually is for use in connection with incinerators for burning of waste materials. The afterburner comprises a main housing 13, and a stack 14 leading from the main housing. The main housing 13 includes an outer metal cover 15, and a refractory brick lining 16 on the interior. The main housing forms a combustion chamber portion indicated at 17. The combustion actually takes place adjacent the left end of the main housing of FIG. 1 and burning continues as the material passes along the chamber 17. The air and products of combustion exhaust out through an exhaust passage 18 that extends laterally from the chamber 17. A screen or other suitable member 19 which keeps large particles from flying out of the afterburner is mounted at the end of passage 18. The screen 19 can be of any desired configuration suitable for the purposes of keeping large particles from being discharged, and also to keep flame from discharging out.

As shown, the chamber 17 is rectangular or square in cross section, and this is seen in FIG. 3. The outer metal housing 15 is attached to the legs 11 in any suitable way, and is formed in any suitable way. The refractory lining 16 is of sufficient thickness to keep the outer metal cover 15 cool even though high temperature combustion is taking place in the chamber 17. The outlet passageway 18 is also rectilinear in cross section, if desired.

The burner for the afterburner unit is indicated generally at 23, and is mounted onto an outwardly extending sleeve 34 having an internal passageway 25 leading to the chamber 17. Passageway 25 also can be rectilinear in cross section, and the passageway 25 forms an initial combustion area for flame from the burner. A centrifugal blower 26 may be provided and mounted with a suitable support 27 onto the top of the afterburner housing. The air inlet for the blower (which is not shown) is in the center of the rotary blower housing, and the blower 26 has an outlet 27 leading into a pipe 28, that has a portion 29 extending down into a burner housing 30.

The burner housing construction is shown in greater detail in FIGS. 4-7. The burner housing 30, as shown, forms a cylindrical chamber and is mounted onto a mounting plate 31 at one end thereof. The pipe 29 joins the chamber formed by the housing 30 adjacent the other end thereof. A gas inlet pipe 34 leading from a suitable gas source (this can be natural gas or LP gas or some other fuel) extends through the wall of pipe 29 and has a right angle blend so that a gas pipe portion 35 extends parallel to the axis of the pipe 29 adjacent the entry opening 36 where the pipe 29 joins the housing 30. The air from the blower 26 passes through the pipe 29 and it swirls around the outlet or pipe portion 35, so that the gas coming out of the pipe section 35 and the blower air are mixed thoroughly before they enter the chamber 37 formed by the housing 30. The chamber 37 provides for expansion and mixing of the gas-air mixture.

The chamber 37 is closed except for the inlet opening 36 and an outlet opening 42 defined in the plate 31 although a sight glass 30A is provided. The outlet opening 42 is covered with a screen member 43 that is held in place in a groove 44 with a suitable snap ring 45. The screen member 43 is stainless steel screen mesh, having 14 openings to the inch with 0.025 inch diameter wire. This makes for a very fine mesh, and each opening in the mesh acts as an outlet orifice for the burner. Thus in a small outlet opening there are hundreds of outlet orifices. The air and gas mixture passes through the screen 43 and is broken up and mixed as it passes through. A pilot light shown schematically at 46 is mounted just adjacentthe opening 42 and screen 43 on the outside of the chamber 37 together with a thermocouple control 47 or a flame rod or electronic flame eye can be used for control. Thus the flame starts in the area just shortly past the screen 43. The thermocouple or flame rod or electronic flame eye and pilot light are of course connected to suitable controls for the burner and gas source shown schematically, in a usual or conventional manner known in the art.

The flame commences burning in the chamber 25 just a short'distance past the end of the plate 31, and a very high or hot flame is then present-in the end area of chamber 17 indicated at 50, which'is right adjacent to a side opening 51 defined in the side wall of the chamber 17. Side opening 51 is open to a smoke pipe 52 leading from an incinerator 53, and carrying the smoke from the burner of the incinerator 53. The smoke generally fails to pass'pollution control standards, and therefore the afterburner is necessary to completely burn up all of the particles that are capable of being burned. The pipe 51 is inclined with respect to the longitudinal axis of chamber 17 as shown. A plurality of baffles 54 are mounted in the opening 51 as shown and extend uprightly in the opening 51. The planes of the baffles 54 are positioned so that they are at an angle to the normal direction of smoke travel from pipe 52 indicated by the arrows. As the smoke strikes these baffles, it must change directions to enter into the chamber 17. This causes the smoke to swirl and break up, and mix thoroughly with the flame that is coming from the chamber 25. The flame is indicated generally by the shade lines adjacent the area 50 in F IG. 1. It is in this area where the flames are at high temperature, and the flames are mixed thoroughly with the smoke swirling into the chamber 17, and thus the particles in the smoke are completely burned at a very high temperature. This burning continues as the smoke from the incinerator passes through the chamber 17 in the direction that is indicated by the arrow 56, and then as the material is discharged up through the outlet opening 18 it cools off, and it discharges out through the screen 19 without any harmful pollutants being present.

The screen 43 of the burner divides up the air-gas mixture prior to burning in very fine streams, and this makes the flame disperse adequately as it enters the area 50 in the combustion chamber. In addition, there are baffle means or other means for causing the smoke to change direction as it enters the combustion area 17, and this causes a thorough mixing of the smoke, air, and flames so that the particles in the smoke are capable of being burned are completely burned.

' Of course, while the rectilinear cross section of the chamber makes'the manufacturing somewhat-easier, the combustion chamber for the afterburner can be desired cross section. However, the idea of having the smoke entering from the incinerator and changing direction just as it enters the combustion area insures that it will slow up,'swirl, form eddies and the like so contacts all of the particles in the smoke entry and complete combustion occurs.

The mesh screen on the outlet for the burner not only provides literally hundreds of tongues of flame into the combustion area for efficient consumption of the smoke, but also the mesh acts as a muffler. ,A high volume of fuel and air can be moved through the burner without the usual loud roar of other burners.

The type of stainless steel used for the burner screen is selected to withstand the temperatures involved. The outlet opening for the burner is normally about one half the diameter of the burner housing and about the same diameter as the air-fuel inlet pipe. A typical burner chamber would be 6 to 8 inches in diameter, and the outlet would be 3 to 4 inches in diameter.

The burner construction with the screen covered outlet permits large volumes of fuel and air to be burned quietly and efficiently.

The blower used also can be regulated as to air flow by suitable dampers or speed control to achieve the proper amount of combustion air. A combustion monitor and analyzer can be placed in the unit.

The afterburner shell also may be made in short sections and then bolted together at the job site for ease of shipping.

What is claimed ,is:

1. An afterburher for an incinerator or the like which has a smoke discharge pipe having a smoke flow direction axis, said afterburnerincluding an elongated combustion chamber-having first and second ends, inlet of said combustion chamber and positioned ona side of said inlet means opposite from said outlet opening, said burner providing a flame, and a plurality of baffles adjacent said inlet means positioned to deflect smoke into a path different from the smoke flow direction axis of said smoke pipe to cause smoke entering said combustion chamber to change direction and mix with the flame from said burner as the smoke moves toward the outlet opening.

2.The combustion specified in claim 1 and a blower creating a higher pressure adjacent said combustion area than at the outlet opening to cause the flame and the smoke to move toward said outlet opening.

3. The combination specified in claim 1 wherein said burner means comprises a chamber, a fuel-source, an air source, an inlet at one end of said chamber for the fuel and air, an outlet opening from said chamber and a mesh screen across said opening to break up the fuel and air passing therethrough into a multitude of streams, and ignition means exterior of said chamber to cause burning of said fuel.

4. The combination chamber of claim 1 wherein said combustion chamber has a central axis lying along the normal flow direction of material therethrough, and said smoke pipe flow direction axis is positioned at an oblique angle to the combustion chamber central axis.

means to position the fuel supply pipe in the path of movement of air from said blower to provide a fuel-air mixture at the inlet of said chamber, said chamber thereby providing an expansion space for mixing of said fuel and air, a wire mesh screen covering said outlet, and means to cause ignition of said fuel-air mixture at the exterior of said mesh screen.

6. The burner of Claim 5 wherein said mesh screen is provided with substantially l4 openings per inch and is made with wire substantially 0.025 inches in diameter.

7. The burner construction of claim 5 wherein said blower has a blower outlet pipe, and said fuel supply pipe includes at least a discharge portion that is concentric with and on the interior of said blower outlet the cross sectional area of said chamber. 

1. An afteRburner for an incinerator or the like which has a smoke discharge pipe having a smoke flow direction axis, said afterburner including an elongated combustion chamber having first and second ends, inlet means adjacent a first end of said combustion chamber and connecting said combustion chamber to said smoke pipe, an outlet opening adjacent a second end of said chamber, a burner means adjacent said first end of said combustion chamber and positioned on a side of said inlet means opposite from said outlet opening, said burner providing a flame, and a plurality of baffles adjacent said inlet means positioned to deflect smoke into a path different from the smoke flow direction axis of said smoke pipe to cause smoke entering said combustion chamber to change direction and mix with the flame from said burner as the smoke moves toward the outlet opening.
 2. The combustion specified in claim 1 and a blower creating a higher pressure adjacent said combustion area than at the outlet opening to cause the flame and the smoke to move toward said outlet opening.
 3. The combination specified in claim 1 wherein said burner means comprises a chamber, a fuel source, an air source, an inlet at one end of said chamber for the fuel and air, an outlet opening from said chamber and a mesh screen across said opening to break up the fuel and air passing therethrough into a multitude of streams, and ignition means exterior of said chamber to cause burning of said fuel.
 4. The combination chamber of claim 1 wherein said combustion chamber has a central axis lying along the normal flow direction of material therethrough, and said smoke pipe flow direction axis is positioned at an oblique angle to the combustion chamber central axis.
 5. A pollution reducing burner construction for an afterburner assembly including a housing, said housing defining a chamber having an inlet and an outlet and being of larger cross sectional area than the inlet, a blower having a blower discharge providing a flow of air to the housing inlet, a gaseous fuel supply pipe, means to position the fuel supply pipe in the path of movement of air from said blower to provide a fuel-air mixture at the inlet of said chamber, said chamber thereby providing an expansion space for mixing of said fuel and air, a wire mesh screen covering said outlet, and means to cause ignition of said fuel-air mixture at the exterior of said mesh screen.
 6. The burner of Claim 5 wherein said mesh screen is provided with substantially 14 openings per inch and is made with wire substantially 0.025 inches in diameter.
 7. The burner construction of claim 5 wherein said blower has a blower outlet pipe, and said fuel supply pipe includes at least a discharge portion that is concentric with and on the interior of said blower outlet pipe and having a fuel discharge opening facing in direction toward the inlet of said chamber, whereby air from said blower surrounds said fuel supply pipe and mixes with fuel as fuel is discharged from said discharge opening and prior to the time the air from said blower enters the inlet of said chamber.
 8. The combination as specified in claim 5 wherein said outlet from said chamber is of smaller area than the cross sectional area of said chamber. 